ABSTRACT
Objective:To investigate the infection of spotted fever group Rickettsiae (SFGR) and Rickettsia mooseri ( R.mooseri) of wild rodents in the field of plague foci in Western Yunnan. Methods:The DNA of liver samples of 2 512 wild rodents captured from the plague foci in Lianghe County, Jianchuan County and Yulong County in Western Yunnan from 2015 to 2016 was extracted by magnetic bead method, and the heat shock protein groEL gene primers were used for nested PCR amplification. Gene sequence splicing and Blast homology comparison were performed using DNAStar 7.1 software and GenBank of the National Center for Biotechnology Information (NCBI) of the United States, respectively, and DNAStar 7.1 and MEGA 6.0 softwares were used to construct phylogenetic trees.Results:The wild rodents infected with SFGR were Mus pahari, Rattus steini, Crocidura attenuata and Suncus murinus (one for each), with a total infection rate of 0.16% (4/2 512); no R.mooseri infection was detected. The SFGR infection rates of wild rodents in the plague foci of Lianghe County and Jianchuan County were 0.49% (3/611) and 0.10% (1/1 029), respectively; no SFGR infection was detected in the wild rodents in the plague foci of Yulong County. The homology analysis showed that the homology between SFGR positive samples and reference sequences was 95.45%-100.00%; some of the groEL gene sequences were highly similar among the four positive samples, and the homology was 89.60%-97.40%. Sequence evolution analysis showed that the sequences of three SFGR positive samples from the plague focus in Lianghe County were clustered in the same branch, and the homology reached 94.40%-97.40%; one positive sample sequence from the plague focus in Jianchuan County was clustered in one branch. Conclusion:SFGR infection rate of wild rodents in the field of plague foci in Western Yunnan is low, and no R.mooseri infection is found.
ABSTRACT
Objective:To learn about the infection and gene polymorphisms of hepatitis E virus (HEV) in murine-shaped animals of plague foci in Yunnan Province.Methods:From July to August 2019, around 16 natural villages (4 in Mile City, 6 in Mangshi and 6 in Lianghe County), which were the foci of domestic plague in Yunnan Province, the murine-shaped animals were captured by the night-time method. The liver RNA was extracted, and the target gene of rat HEV was detected by one-step real-time fluorescence quantitative PCR, and the positive rate of rat HEV was calculated. The rat HEV positive samples were amplified by PCR for further clone sequencing, and the resulting sequences were compared with the HEV sequences registered in the GenBank and a phylogenetic tree was constructed by using MegAlign and MEGA 7.0.Results:A total of 491 murine-shaped animals were captured from 3 orders, 5 families, 8 genera, 15 species, and the positive rate of rat HEV was 4.89% (24/491). Among them, the positive rate of Rattus tanezumi and Niviventer fulvescens was 9.39% (23/245) and 1/3, respectively; and other species were negative. There was a statistically significant difference in the positive rate of rat HEV between different habitats ( P = 0.014), and the positive rate of rat HEV in the habitats near the dwellings was higher than that in other habitats ( P < 0.05). The sequence comparison analysis showed that the gene sequence of P018 from Lianghe County was 100.0% homologous to the MG813927.1 sequence of the first patient with rat HEV in Hongkong, and it was clustered into the same branch with the sequences of MG813927.1 and LC549185.1 from rat, was the type HEV C. G024 from Mangshi shared a low homology (20.7% - 31.5%) with other virus strains, and it was clustered into the same branch with a HEV sequence from an avian (AY535004.1). Conclusions:Rat HEV is prevalent in murine-shaped animals of plague foci of Yunnan Province, and there may be gene polymorphisms of rat HEV. In addition, the difference infection rate may be related to the habitats.
ABSTRACT
Objective:To detect and analyze the contents of eight metal elements in water samples of plague foci in Yunnan Province.Methods:During the period from December 2015 to November 2016, the plague foci of Yulong, Jianchuan and Lianghe were selected as sampling sites, water samples were collected in areas with rodent activities in the 4 seasons of spring, summer, autumn and winter. The contents of eight metal elements calcium (Ca), iron (Fe), zinc (Zn), chromium (Cr), plumbum (Pb), manganese (Mn), cadmium (Cd) and cuprum (Cu) in water samples were measured by flame atomic absorption spectrometry (FAAS), and the data [median (interquartile distance)] were statistically analyzed.Results:Twenty-six, 58 and 54 water samples were collected from Yulong, Jianchuan and Lianghe plague foci, respectively. The contents of metal elements of Pb and Cd in water samples of the three plague foci [Yulong: 0.19 (0.78) and 0.08 (0.07) mg/L; Jianchuan: 0.23 (0.56) and 0.03 (0.06) mg/L; Lianghe: 0.13 (0.61) and 0.09 (0.08) mg/L] were higher than that of "Environmental Quality Standards for Surface Water" (Pb: 0.10 mg/L, Cd: 0.01 mg/L). There were significant differences in the contents of Ca and Cd elements among the three regions ( P < 0.05), but there was no significant difference in the contents of the other 6 metal elements among the three regions ( P > 0.05). The content of Ca element was the highest in Yulong plague foci, and the lowest in Lianghe plague foci ( P < 0.017). In the Yulong plague foci, there was no statistically significant difference in the content of Fe element in different seasons ( P > 0.05), and the differences in the contents of the other 7 metal elements were statistically significant ( P < 0.05). There was no significant difference in the content of Cr element in Jianchuan plague foci in different seasons ( P > 0.05), and the differences in the content of the other 7 metal elements were statistically significant ( P < 0.05). There was no significant difference in the content of Ca element in Lianghe plague foci in different seasons ( P > 0.05), and the differences in the content of the other 7 metal elements were statistically significant ( P < 0.05). Conclusion:The metal element contents of Pb and Cd are relatively abundant in water samples from 3 plague foci of Yunnan Province, and the seasonal variation trend of metal element content in water samples of Yulong and Jianchuan plague foci is similar.